Handling minimum required communication range in sidelink communication

ABSTRACT

A method and apparatus for handling a minimum required communication range in sidelink communication is provided. A first wireless device, which is performing transmission with a second wireless device, detects that the second wireless device is out of a minimum required communication range, and suspends the transmission with the second wireless device.

TECHNICAL FIELD

The present disclosure relates to handling a minimum requiredcommunication range in sidelink communication.

BACKGROUND

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

Work has started in international telecommunication union (ITU) and 3GPPto develop requirements and specifications for new radio (NR) systems.3GPP has to identify and develop the technology components needed forsuccessfully standardizing the new RAT timely satisfying both the urgentmarket needs, and the more long-term requirements set forth by the ITUradio communication sector (ITU-R) international mobiletelecommunications (IMT)-2020 process. Further, the NR should be able touse any spectrum band ranging at least up to 100 GHz that may be madeavailable for wireless communications even in a more distant future.

The NR targets a single technical framework addressing all usagescenarios, requirements and deployment scenarios including enhancedmobile broadband (eMBB), massive machine-type-communications (mMTC),ultra-reliable and low latency communications (URLLC), etc. The NR shallbe inherently forward compatible.

Vehicle-to-everything (V2X) communication is the passing of informationfrom a vehicle to any entity that may affect the vehicle, and viceversa. It is a vehicular communication system that incorporates othermore specific types of communication as vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), vehicle-to-vehicle (V2V),vehicle-to-pedestrian (V2P), vehicle-to-device (V2D) and vehicle-to-grid(V2G).

SUMMARY

In sidelink and/or V2X sidelink for 5G NR, a minimum requiredcommunication range is introduced for unicast and/or groupcommunication. For establishing a connection between wireless devices,the minimum required communication range should be considered.

In an aspect, a method for a first wireless device in a wirelesscommunication system is provided. The method includes detecting that asecond wireless device is out of a minimum required communication range,and suspending transmission with the second wireless device.

In another aspect, an apparatus for implementing the above method isprovided.

The present disclosure can have various advantageous effects.

For example, one wireless device can perform fast and reliable sidelinkcommunication for unicast and/or groupcast (or group communication) tosupport a minimum required communication range by minimizing inefficientsignalling overheads.

For example, a system can provide fast and reliable sidelinkcommunication for unicast and/or groupcast (or group communication) tosupport a minimum required communication range.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a communication system to whichimplementations of the present disclosure is applied.

FIG. 2 shows an example of wireless devices to which implementations ofthe present disclosure is applied.

FIG. 3 shows an example of a wireless device to which implementations ofthe present disclosure is applied.

FIG. 4 shows another example of wireless devices to whichimplementations of the present disclosure is applied.

FIG. 5 shows an example of UE to which implementations of the presentdisclosure is applied.

FIGS. 6 and 7 show an example of protocol stacks in a 3GPP basedwireless communication system to which implementations of the presentdisclosure is applied.

FIG. 8 shows a frame structure in a 3GPP based wireless communicationsystem to which implementations of the present disclosure is applied.

FIG. 9 shows a data flow example in the 3GPP NR system to whichimplementations of the present disclosure is applied.

FIGS. 10 and 11 show an example of PC5 protocol stacks to whichimplementations of the present disclosure is applied.

FIG. 12 shows an example of PC5 link setup to which implementations ofthe present disclosure is applied.

FIG. 13 shows an example of security mode control to whichimplementations of the present disclosure is applied.

FIG. 14 shows an example of PC5 link release to which implementations ofthe present disclosure is applied.

FIG. 15 shows an example of direct link keepalive procedure to whichimplementations of the present disclosure is applied.

FIG. 16 shows an example of UE oriented layer 2 link establishmentprocedure to which implementations of the present disclosure is applied.

FIG. 17 shows an example of V2X service oriented layer 2 linkestablishment procedure to which implementations of the presentdisclosure is applied.

FIG. 18 shows an example of a method for a first wireless device towhich implementations of the present disclosure is applied.

FIG. 19 shows an example of a method for establishing a connection by aninitiating/detecting wireless device to which implementations of thepresent disclosure is applied.

FIG. 20 shows an example of a method for establishing a connection by apeer/target wireless device to which implementations of the presentdisclosure is applied.

FIG. 21 shows an example of supporting a minimum required communicationrange between two UEs according to implementations of the presentdisclosure.

FIG. 22 shows another example of supporting a minimum requiredcommunication range between two UEs according to implementations of thepresent disclosure.

FIG. 23 shows another example of supporting a minimum requiredcommunication range between two UEs according to implementations of thepresent disclosure.

DETAILED DESCRIPTION

The following techniques, apparatuses, and systems may be applied to avariety of wireless multiple access systems. Examples of the multipleaccess systems include a code division multiple access (CDMA) system, afrequency division multiple access (FDMA) system, a time divisionmultiple access (TDMA) system, an orthogonal frequency division multipleaccess (OFDMA) system, a single carrier frequency division multipleaccess (SC-FDMA) system, and a multicarrier frequency division multipleaccess (MC-FDMA) system. CDMA may be embodied through radio technologysuch as universal terrestrial radio access (UTRA) or CDMA2000. TDMA maybe embodied through radio technology such as global system for mobilecommunications (GSM), general packet radio service (GPRS), or enhanceddata rates for GSM evolution (EDGE). OFDMA may be embodied through radiotechnology such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA(E-UTRA). UTRA is a part of a universal mobile telecommunications system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employsOFDMA in DL and SC-FDMA in UL. LTE-advanced (LTE-A) is an evolvedversion of 3GPP LTE.

For convenience of description, implementations of the presentdisclosure are mainly described in regards to a 3GPP based wirelesscommunication system. However, the technical features of the presentdisclosure are not limited thereto. For example, although the followingdetailed description is given based on a mobile communication systemcorresponding to a 3GPP based wireless communication system, aspects ofthe present disclosure that are not limited to 3GPP based wirelesscommunication system are applicable to other mobile communicationsystems.

For terms and technologies which are not specifically described amongthe terms of and technologies employed in the present disclosure, thewireless communication standard documents published before the presentdisclosure may be referenced.

In the present disclosure, “A or B” may mean “only A”, “only B”, or“both A and B”. In other words, “A or B” in the present disclosure maybe interpreted as “A and/or B”. For example, “A, B or C” in the presentdisclosure may mean “only A”, “only B”, “only C”, or “any combination ofA, B and C”.

In the present disclosure, slash (/) or comma (,) may mean “and/or”. Forexample, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean “onlyA”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, Bor C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B” or “both A and B”. In addition, the expression “at least one ofA or B” or “at least one of A and/or B” in the present disclosure may beinterpreted as same as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B and C” maymean “only A”, “only B”, “only C”, or “any combination of A, B and C”.In addition, “at least one of A, B or C” or “at least one of A, B and/orC” may mean “at least one of A, B and C”.

Also, parentheses used in the present disclosure may mean “for example”.In detail, when it is shown as “control information (PDCCH)”, “PDCCH”may be proposed as an example of “control information”. In other words,“control information” in the present disclosure is not limited to“PDCCH”, and “PDDCH” may be proposed as an example of “controlinformation”. In addition, even when shown as “control information(i.e., PDCCH)”, “PDCCH” may be proposed as an example of “controlinformation”.

Technical features that are separately described in one drawing in thepresent disclosure may be implemented separately or simultaneously.

Although not limited thereto, various descriptions, functions,procedures, suggestions, methods and/or operational flowcharts of thepresent disclosure disclosed herein can be applied to various fieldsrequiring wireless communication and/or connection (e.g., 5G) betweendevices.

Hereinafter, the present disclosure will be described in more detailwith reference to drawings. The same reference numerals in the followingdrawings and/or descriptions may refer to the same and/or correspondinghardware blocks, software blocks, and/or functional blocks unlessotherwise indicated.

FIG. 1 shows an example of a communication system to whichimplementations of the present disclosure is applied.

The 5G usage scenarios shown in FIG. 1 are only exemplary, and thetechnical features of the present disclosure can be applied to other 5Gusage scenarios which are not shown in FIG. 1.

Three main requirement categories for 5G include (1) a category ofenhanced mobile broadband (eMBB), (2) a category of massive machine typecommunication (mMTC), and (3) a category of ultra-reliable and lowlatency communications (URLLC).

Partial use cases may require a plurality of categories for optimizationand other use cases may focus only upon one key performance indicator(KPI). 5G supports such various use cases using a flexible and reliablemethod.

eMBB far surpasses basic mobile Internet access and covers abundantbidirectional work and media and entertainment applications in cloud andaugmented reality. Data is one of 5G core motive forces and, in a 5Gera, a dedicated voice service may not be provided for the first time.In 5G, it is expected that voice will be simply processed as anapplication program using data connection provided by a communicationsystem. Main causes for increased traffic volume are due to an increasein the size of content and an increase in the number of applicationsrequiring high data transmission rate. A streaming service (of audio andvideo), conversational video, and mobile Internet access will be morewidely used as more devices are connected to the Internet. These manyapplication programs require connectivity of an always turned-on statein order to push real-time information and alarm for users. Cloudstorage and applications are rapidly increasing in a mobilecommunication platform and may be applied to both work andentertainment. The cloud storage is a special use case which acceleratesgrowth of uplink data transmission rate. 5G is also used for remote workof cloud. When a tactile interface is used, 5G demands much lowerend-to-end latency to maintain user good experience. Entertainment, forexample, cloud gaming and video streaming, is another core element whichincreases demand for mobile broadband capability. Entertainment isessential for a smartphone and a tablet in any place including highmobility environments such as a train, a vehicle, and an airplane. Otheruse cases are augmented reality for entertainment and informationsearch. In this case, the augmented reality requires very low latencyand instantaneous data volume.

In addition, one of the most expected 5G use cases relates a functioncapable of smoothly connecting embedded sensors in all fields, i.e.,mMTC. It is expected that the number of potential Internet-of-things(IoT) devices will reach 204 hundred million up to the year of 2020. Anindustrial IoT is one of categories of performing a main role enabling asmart city, asset tracking, smart utility, agriculture, and securityinfrastructure through 5G.

URLLC includes a new service that will change industry through remotecontrol of main infrastructure and an ultra-reliable/availablelow-latency link such as a self-driving vehicle. A level of reliabilityand latency is essential to control a smart grid, automatize industry,achieve robotics, and control and adjust a drone.

5G is a means of providing streaming evaluated as a few hundred megabitsper second to gigabits per second and may complement fiber-to-the-home(FTTH) and cable-based broadband (or DOCSIS). Such fast speed is neededto deliver TV in resolution of 4K or more (6K, 8K, and more), as well asvirtual reality and augmented reality. Virtual reality (VR) andaugmented reality (AR) applications include almost immersive sportsgames. A specific application program may require a special networkconfiguration. For example, for VR games, gaming companies need toincorporate a core server into an edge network server of a networkoperator in order to minimize latency.

Automotive is expected to be a new important motivated force in 5Gtogether with many use cases for mobile communication for vehicles. Forexample, entertainment for passengers requires high simultaneouscapacity and mobile broadband with high mobility. This is because futureusers continue to expect connection of high quality regardless of theirlocations and speeds. Another use case of an automotive field is an ARdashboard. The AR dashboard causes a driver to identify an object in thedark in addition to an object seen from a front window and displays adistance from the object and a movement of the object by overlappinginformation talking to the driver. In the future, a wireless moduleenables communication between vehicles, information exchange between avehicle and supporting infrastructure, and information exchange betweena vehicle and other connected devices (e.g., devices accompanied by apedestrian). A safety system guides alternative courses of a behavior sothat a driver may drive more safely drive, thereby lowering the dangerof an accident. The next stage will be a remotely controlled orself-driven vehicle. This requires very high reliability and very fastcommunication between different self-driven vehicles and between avehicle and infrastructure. In the future, a self-driven vehicle willperform all driving activities and a driver will focus only uponabnormal traffic that the vehicle cannot identify. Technicalrequirements of a self-driven vehicle demand ultra-low latency andultra-high reliability so that traffic safety is increased to a levelthat cannot be achieved by human being.

A smart city and a smart home/building mentioned as a smart society willbe embedded in a high-density wireless sensor network. A distributednetwork of an intelligent sensor will identify conditions for costs andenergy-efficient maintenance of a city or a home. Similar configurationsmay be performed for respective households. All of temperature sensors,window and heating controllers, burglar alarms, and home appliances arewirelessly connected. Many of these sensors are typically low in datatransmission rate, power, and cost. However, real-time HD video may bedemanded by a specific type of device to perform monitoring.

Consumption and distribution of energy including heat or gas isdistributed at a higher level so that automated control of thedistribution sensor network is demanded. The smart grid collectsinformation and connects the sensors to each other using digitalinformation and communication technology so as to act according to thecollected information. Since this information may include behaviors of asupply company and a consumer, the smart grid may improve distributionof fuels such as electricity by a method having efficiency, reliability,economic feasibility, production sustainability, and automation. Thesmart grid may also be regarded as another sensor network having lowlatency.

Mission critical application (e.g., e-health) is one of 5G usescenarios. A health part contains many application programs capable ofenjoying benefit of mobile communication. A communication system maysupport remote treatment that provides clinical treatment in a farawayplace. Remote treatment may aid in reducing a barrier against distanceand improve access to medical services that cannot be continuouslyavailable in a faraway rural area. Remote treatment is also used toperform important treatment and save lives in an emergency situation.The wireless sensor network based on mobile communication may provideremote monitoring and sensors for parameters such as heart rate andblood pressure.

Wireless and mobile communication gradually becomes important in thefield of an industrial application. Wiring is high in installation andmaintenance cost. Therefore, a possibility of replacing a cable withreconstructible wireless links is an attractive opportunity in manyindustrial fields. However, in order to achieve this replacement, it isnecessary for wireless connection to be established with latency,reliability, and capacity similar to those of the cable and managementof wireless connection needs to be simplified. Low latency and a verylow error probability are new requirements when connection to 5G isneeded.

Logistics and freight tracking are important use cases for mobilecommunication that enables inventory and package tracking anywhere usinga location-based information system. The use cases of logistics andfreight typically demand low data rate but require location informationwith a wide range and reliability.

Referring to FIG. 1, the communication system 1 includes wirelessdevices 100 a to 100 f, base stations (BSs) 200, and a network 300.Although FIG. 1 illustrates a 5G network as an example of the network ofthe communication system 1, the implementations of the presentdisclosure are not limited to the 5G system, and can be applied to thefuture communication system beyond the 5G system.

The BSs 200 and the network 300 may be implemented as wireless devicesand a specific wireless device may operate as a BS/network node withrespect to other wireless devices.

The wireless devices 100 a to 100 f represent devices performingcommunication using radio access technology (RAT) (e.g., 5G new RAT(NR)) or LTE) and may be referred to as communication/radio/5G devices.The wireless devices 100 a to 100 f may include, without being limitedto, a robot 100 a, vehicles 100 b-1 and 100 b-2, an extended reality(XR) device 100 c, a hand-held device 100 d, a home appliance 100 e, anIoT device 100 f, and an artificial intelligence (AI) device/server 400.For example, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous driving vehicle, and a vehiclecapable of performing communication between vehicles. The vehicles mayinclude an unmanned aerial vehicle (UAV) (e.g., a drone). The XR devicemay include an AR/VR/Mixed Reality (MR) device and may be implemented inthe form of a head-mounted device (HMD), a head-up display (HUD) mountedin a vehicle, a television, a smartphone, a computer, a wearable device,a home appliance device, a digital signage, a vehicle, a robot, etc. Thehand-held device may include a smartphone, a smartpad, a wearable device(e.g., a smartwatch or a smartglasses), and a computer (e.g., anotebook). The home appliance may include a TV, a refrigerator, and awashing machine. The IoT device may include a sensor and a smartmeter.

In the present disclosure, the wireless devices 100 a to 100 f may becalled user equipments (UEs). A UE may include, for example, a cellularphone, a smartphone, a laptop computer, a digital broadcast terminal, apersonal digital assistant (PDA), a portable multimedia player (PMP), anavigation system, a slate personal computer (PC), a tablet PC, anultrabook, a vehicle, a vehicle having an autonomous traveling function,a connected car, an UAV, an AI module, a robot, an AR device, a VRdevice, an MR device, a hologram device, a public safety device, an MTCdevice, an IoT device, a medical device, a FinTech device (or afinancial device), a security device, a weather/environment device, adevice related to a 5G service, or a device related to a fourthindustrial revolution field.

The UAV may be, for example, an aircraft aviated by a wireless controlsignal without a human being onboard.

The VR device may include, for example, a device for implementing anobject or a background of the virtual world. The AR device may include,for example, a device implemented by connecting an object or abackground of the virtual world to an object or a background of the realworld. The MR device may include, for example, a device implemented bymerging an object or a background of the virtual world into an object ora background of the real world. The hologram device may include, forexample, a device for implementing a stereoscopic image of 360 degreesby recording and reproducing stereoscopic information, using aninterference phenomenon of light generated when two laser lights calledholography meet.

The public safety device may include, for example, an image relay deviceor an image device that is wearable on the body of a user.

The MTC device and the IoT device may be, for example, devices that donot require direct human intervention or manipulation. For example, theMTC device and the IoT device may include smartmeters, vending machines,thermometers, smartbulbs, door locks, or various sensors.

The medical device may be, for example, a device used for the purpose ofdiagnosing, treating, relieving, curing, or preventing disease. Forexample, the medical device may be a device used for the purpose ofdiagnosing, treating, relieving, or correcting injury or impairment. Forexample, the medical device may be a device used for the purpose ofinspecting, replacing, or modifying a structure or a function. Forexample, the medical device may be a device used for the purpose ofadjusting pregnancy. For example, the medical device may include adevice for treatment, a device for operation, a device for (in vitro)diagnosis, a hearing aid, or a device for procedure.

The security device may be, for example, a device installed to prevent adanger that may arise and to maintain safety. For example, the securitydevice may be a camera, a closed-circuit TV (CCTV), a recorder, or ablack box.

The FinTech device may be, for example, a device capable of providing afinancial service such as mobile payment. For example, the FinTechdevice may include a payment device or a point of sales (POS) system.

The weather/environment device may include, for example, a device formonitoring or predicting a weather/environment.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR)network, and a beyond-5G network. Although the wireless devices 100 a to100 f may communicate with each other through the BSs 200/network 300,the wireless devices 100 a to 100 f may perform direct communication(e.g., sidelink communication) with each other without passing throughthe BSs 200/network 300. For example, the vehicles 100 b-1 and 100 b-2may perform direct communication (e.g., vehicle-to-vehicle(V2V)/vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b and 150 c may beestablished between the wireless devices 100 a to 100 f and/or betweenwireless device 100 a to 100 f and BS 200 and/or between BSs 200.Herein, the wireless communication/connections may be establishedthrough various RATs (e.g., 5G NR) such as uplink/downlink communication150 a, sidelink communication (or device-to-device (D2D) communication)150 b, inter-base station communication 150 c (e.g., relay, integratedaccess and backhaul (IAB)), etc. The wireless devices 100 a to 100 f andthe BSs 200/the wireless devices 100 a to 100 f may transmit/receiveradio signals to/from each other through the wirelesscommunication/connections 150 a, 150 b and 150 c. For example, thewireless communication/connections 150 a, 150 b and 150 c maytransmit/receive signals through various physical channels. To this end,at least a part of various configuration information configuringprocesses, various signal processing processes (e.g., channelencoding/decoding, modulation/demodulation, and resourcemapping/de-mapping), and resource allocating processes, fortransmitting/receiving radio signals, may be performed based on thevarious proposals of the present disclosure.

FIG. 2 shows an example of wireless devices to which implementations ofthe present disclosure is applied.

Referring to FIG. 2, a first wireless device 100 and a second wirelessdevice 200 may transmit/receive radio signals to/from an external devicethrough a variety of RATs (e.g., LTE and NR). In FIG. 2, {the firstwireless device 100 and the second wireless device 200} may correspondto at least one of {the wireless device 100 a to 100 f and the BS 200},{the wireless device 100 a to 100 f and the wireless device 100 a to 100f} and/or {the BS 200 and the BS 200} of FIG. 1.

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,suggestions, methods and/or operational flowcharts described in thepresent disclosure. For example, the processor(s) 102 may processinformation within the memory(s) 104 to generate firstinformation/signals and then transmit radio signals including the firstinformation/signals through the transceiver(s) 106. The processor(s) 102may receive radio signals including second information/signals throughthe transceiver(s) 106 and then store information obtained by processingthe second information/signals in the memory(s) 104. The memory(s) 104may be connected to the processor(s) 102 and may store a variety ofinformation related to operations of the processor(s) 102. For example,the memory(s) 104 may store software code including commands forperforming a part or the entirety of processes controlled by theprocessor(s) 102 or for performing the descriptions, functions,procedures, suggestions, methods and/or operational flowcharts describedin the present disclosure. Herein, the processor(s) 102 and thememory(s) 104 may be a part of a communication modem/circuit/chipdesigned to implement RAT (e.g., LTE or NR). The transceiver(s) 106 maybe connected to the processor(s) 102 and transmit and/or receive radiosignals through one or more antennas 108. Each of the transceiver(s) 106may include a transmitter and/or a receiver. The transceiver(s) 106 maybe interchangeably used with radio frequency (RF) unit(s). In thepresent disclosure, the first wireless device 100 may represent acommunication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,suggestions, methods and/or operational flowcharts described in thepresent disclosure. For example, the processor(s) 202 may processinformation within the memory(s) 204 to generate thirdinformation/signals and then transmit radio signals including the thirdinformation/signals through the transceiver(s) 206. The processor(s) 202may receive radio signals including fourth information/signals throughthe transceiver(s) 106 and then store information obtained by processingthe fourth information/signals in the memory(s) 204. The memory(s) 204may be connected to the processor(s) 202 and may store a variety ofinformation related to operations of the processor(s) 202. For example,the memory(s) 204 may store software code including commands forperforming a part or the entirety of processes controlled by theprocessor(s) 202 or for performing the descriptions, functions,procedures, suggestions, methods and/or operational flowcharts describedin the present disclosure. Herein, the processor(s) 202 and thememory(s) 204 may be a part of a communication modem/circuit/chipdesigned to implement RAT (e.g., LTE or NR). The transceiver(s) 206 maybe connected to the processor(s) 202 and transmit and/or receive radiosignals through one or more antennas 208. Each of the transceiver(s) 206may include a transmitter and/or a receiver. The transceiver(s) 206 maybe interchangeably used with RF unit(s). In the present disclosure, thesecond wireless device 200 may represent a communicationmodem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as physical (PHY)layer, media access control (MAC) layer, radio link control (RLC) layer,packet data convergence protocol (PDCP) layer, radio resource control(RRC) layer, and service data adaptation protocol (SDAP) layer). The oneor more processors 102 and 202 may generate one or more protocol dataunits (PDUs) and/or one or more service data unit (SDUs) according tothe descriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure. The one ormore processors 102 and 202 may generate messages, control information,data, or information according to the descriptions, functions,procedures, suggestions, methods and/or operational flowcharts disclosedin the present disclosure. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure and providethe generated signals to the one or more transceivers 106 and 206. Theone or more processors 102 and 202 may receive the signals (e.g.,baseband signals) from the one or more transceivers 106 and 206 andacquire the PDUs, SDUs, messages, control information, data, orinformation according to the descriptions, functions, procedures,suggestions, methods and/or operational flowcharts disclosed in thepresent disclosure.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreapplication specific integrated circuits (ASICs), one or more digitalsignal processors (DSPs), one or more digital signal processing devices(DSPDs), one or more programmable logic devices (PLDs), or one or morefield programmable gate arrays (FPGAs) may be included in the one ormore processors 102 and 202. descriptions, functions, procedures,suggestions, methods and/or operational flowcharts disclosed in thepresent disclosure may be implemented using firmware or software and thefirmware or software may be configured to include the modules,procedures, or functions. Firmware or software configured to perform thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure may beincluded in the one or more processors 102 and 202 or stored in the oneor more memories 104 and 204 so as to be driven by the one or moreprocessors 102 and 202. The descriptions, functions, procedures,suggestions, methods and/or operational flowcharts disclosed in thepresent disclosure may be implemented using firmware or software in theform of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by read-onlymemories (ROMs), random access memories (RAMs), electrically erasableprogrammable read-only memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure, to one ormore other devices. The one or more transceivers 106 and 206 may receiveuser data, control information, and/or radio signals/channels, mentionedin the descriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure, from one ormore other devices. For example, the one or more transceivers 106 and206 may be connected to the one or more processors 102 and 202 andtransmit and receive radio signals. For example, the one or moreprocessors 102 and 202 may perform control so that the one or moretransceivers 106 and 206 may transmit user data, control information, orradio signals to one or more other devices. The one or more processors102 and 202 may perform control so that the one or more transceivers 106and 206 may receive user data, control information, or radio signalsfrom one or more other devices.

The one or more transceivers 106 and 206 may be connected to the one ormore antennas 108 and 208 and the one or more transceivers 106 and 206may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure, through theone or more antennas 108 and 208. In the present disclosure, the one ormore antennas may be a plurality of physical antennas or a plurality oflogical antennas (e.g., antenna ports).

The one or more transceivers 106 and 206 may convert received radiosignals/channels, etc., from RF band signals into baseband signals inorder to process received user data, control information, radiosignals/channels, etc., using the one or more processors 102 and 202.The one or more transceivers 106 and 206 may convert the user data,control information, radio signals/channels, etc., processed using theone or more processors 102 and 202 from the base band signals into theRF band signals. To this end, the one or more transceivers 106 and 206may include (analog) oscillators and/or filters. For example, thetransceivers 106 and 206 can up-convert OFDM baseband signals to acarrier frequency by their (analog) oscillators and/or filters under thecontrol of the processors 102 and 202 and transmit the up-converted OFDMsignals at the carrier frequency. The transceivers 106 and 206 mayreceive OFDM signals at a carrier frequency and down-convert the OFDMsignals into OFDM baseband signals by their (analog) oscillators and/orfilters under the control of the transceivers 102 and 202.

In the implementations of the present disclosure, a UE may operate as atransmitting device in uplink (UL) and as a receiving device in downlink(DL). In the implementations of the present disclosure, a BS may operateas a receiving device in UL and as a transmitting device in DL.Hereinafter, for convenience of description, it is mainly assumed thatthe first wireless device 100 acts as the UE, and the second wirelessdevice 200 acts as the BS. For example, the processor(s) 102 connectedto, mounted on or launched in the first wireless device 100 may beconfigured to perform the UE behavior according to an implementation ofthe present disclosure or control the transceiver(s) 106 to perform theUE behavior according to an implementation of the present disclosure.The processor(s) 202 connected to, mounted on or launched in the secondwireless device 200 may be configured to perform the BS behavioraccording to an implementation of the present disclosure or control thetransceiver(s) 206 to perform the BS behavior according to animplementation of the present disclosure.

In the present disclosure, a BS is also referred to as a node B (NB), aneNode B (eNB), or a gNB.

FIG. 3 shows an example of a wireless device to which implementations ofthe present disclosure is applied.

The wireless device may be implemented in various forms according to ause-case/service (refer to FIG. 1).

Referring to FIG. 3, wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 2 and may be configured by variouselements, components, units/portions, and/or modules. For example, eachof the wireless devices 100 and 200 may include a communication unit110, a control unit 120, a memory unit 130, and additional components140. The communication unit 110 may include a communication circuit 112and transceiver(s) 114. For example, the communication circuit 112 mayinclude the one or more processors 102 and 202 of FIG. 2 and/or the oneor more memories 104 and 204 of FIG. 2. For example, the transceiver(s)114 may include the one or more transceivers 106 and 206 of FIG. 2and/or the one or more antennas 108 and 208 of FIG. 2. The control unit120 is electrically connected to the communication unit 110, the memory130, and the additional components 140 and controls overall operation ofeach of the wireless devices 100 and 200. For example, the control unit120 may control an electric/mechanical operation of each of the wirelessdevices 100 and 200 based on programs/code/commands/information storedin the memory unit 130. The control unit 120 may transmit theinformation stored in the memory unit 130 to the exterior (e.g., othercommunication devices) via the communication unit 110 through awireless/wired interface or store, in the memory unit 130, informationreceived through the wireless/wired interface from the exterior (e.g.,other communication devices) via the communication unit 110.

The additional components 140 may be variously configured according totypes of the wireless devices 100 and 200. For example, the additionalcomponents 140 may include at least one of a power unit/battery,input/output (I/O) unit (e.g., audio I/O port, video I/O port), adriving unit, and a computing unit. The wireless devices 100 and 200 maybe implemented in the form of, without being limited to, the robot (100a of FIG. 1), the vehicles (100 b-1 and 100 b-2 of FIG. 1), the XRdevice (100 c of FIG. 1), the hand-held device (100 d of FIG. 1), thehome appliance (100 e of FIG. 1), the IoT device (100 f of FIG. 1), adigital broadcast terminal, a hologram device, a public safety device,an MTC device, a medicine device, a FinTech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 1), the BSs (200 of FIG. 1), a network node,etc. The wireless devices 100 and 200 may be used in a mobile or fixedplace according to a use-example/service.

In FIG. 3, the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor (AP), an electronic control unit(ECU), a graphical processing unit, and a memory control processor. Asanother example, the memory 130 may be configured by a RAM, a DRAM, aROM, a flash memory, a volatile memory, a non-volatile memory, and/or acombination thereof.

FIG. 4 shows another example of wireless devices to whichimplementations of the present disclosure is applied.

Referring to FIG. 4, wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 2 and may be configured by variouselements, components, units/portions, and/or modules.

The first wireless device 100 may include at least one transceiver, suchas a transceiver 106, and at least one processing chip, such as aprocessing chip 101. The processing chip 101 may include at least oneprocessor, such a processor 102, and at least one memory, such as amemory 104. The memory 104 may be operably connectable to the processor102. The memory 104 may store various types of information and/orinstructions. The memory 104 may store a software code 105 whichimplements instructions that, when executed by the processor 102,perform the descriptions, functions, procedures, suggestions, methodsand/or operational flowcharts disclosed in the present disclosure. Forexample, the software code 105 may implement instructions that, whenexecuted by the processor 102, perform the descriptions, functions,procedures, suggestions, methods and/or operational flowcharts disclosedin the present disclosure. For example, the software code 105 maycontrol the processor 102 to perform one or more protocols. For example,the software code 105 may control the processor 102 may perform one ormore layers of the radio interface protocol.

The second wireless device 200 may include at least one transceiver,such as a transceiver 206, and at least one processing chip, such as aprocessing chip 201. The processing chip 201 may include at least oneprocessor, such a processor 202, and at least one memory, such as amemory 204. The memory 204 may be operably connectable to the processor202. The memory 204 may store various types of information and/orinstructions. The memory 204 may store a software code 205 whichimplements instructions that, when executed by the processor 202,perform the descriptions, functions, procedures, suggestions, methodsand/or operational flowcharts disclosed in the present disclosure. Forexample, the software code 205 may implement instructions that, whenexecuted by the processor 202, perform the descriptions, functions,procedures, suggestions, methods and/or operational flowcharts disclosedin the present disclosure. For example, the software code 205 maycontrol the processor 202 to perform one or more protocols. For example,the software code 205 may control the processor 202 may perform one ormore layers of the radio interface protocol.

FIG. 5 shows an example of UE to which implementations of the presentdisclosure is applied.

Referring to FIG. 5, a UE 100 may correspond to the first wirelessdevice 100 of FIG. 2 and/or the first wireless device 100 of FIG. 4.

A UE 100 includes a processor 102, a memory 104, a transceiver 106, oneor more antennas 108, a power management module 110, a battery 1112, adisplay 114, a keypad 116, a subscriber identification module (SIM) card118, a speaker 120, and a microphone 122.

The processor 102 may be configured to implement the descriptions,functions, procedures, suggestions, methods and/or operationalflowcharts disclosed in the present disclosure. The processor 102 may beconfigured to control one or more other components of the UE 100 toimplement the descriptions, functions, procedures, suggestions, methodsand/or operational flowcharts disclosed in the present disclosure.Layers of the radio interface protocol may be implemented in theprocessor 102. The processor 102 may include ASIC, other chipset, logiccircuit and/or data processing device. The processor 102 may be anapplication processor. The processor 102 may include at least one of adigital signal processor (DSP), a central processing unit (CPU), agraphics processing unit (GPU), a modem (modulator and demodulator). Anexample of the processor 102 may be found in SNAPDRAGON™ series ofprocessors made by Qualcomm®, EXYNOS™ series of processors made bySamsung®, A series of processors made by Apple®, HELIO™ series ofprocessors made by MediaTek®, ATOM™ series of processors made by Intel®or a corresponding next generation processor.

The memory 104 is operatively coupled with the processor 102 and storesa variety of information to operate the processor 102. The memory 104may include ROM, RAM, flash memory, memory card, storage medium and/orother storage device.

When the embodiments are implemented in software, the techniquesdescribed herein can be implemented with modules (e.g., procedures,functions, etc.) that perform the descriptions, functions, procedures,suggestions, methods and/or operational flowcharts disclosed in thepresent disclosure. The modules can be stored in the memory 104 andexecuted by the processor 102. The memory 104 can be implemented withinthe processor 102 or external to the processor 102 in which case thosecan be communicatively coupled to the processor 102 via various means asis known in the art.

The transceiver 106 is operatively coupled with the processor 102, andtransmits and/or receives a radio signal. The transceiver 106 includes atransmitter and a receiver. The transceiver 106 may include basebandcircuitry to process radio frequency signals. The transceiver 106controls the one or more antennas 108 to transmit and/or receive a radiosignal.

The power management module 110 manages power for the processor 102and/or the transceiver 106. The battery 112 supplies power to the powermanagement module 110.

The display 114 outputs results processed by the processor 102. Thekeypad 116 receives inputs to be used by the processor 102. The keypad16 may be shown on the display 114.

The SIM card 118 is an integrated circuit that is intended to securelystore the international mobile subscriber identity (IMSI) number and itsrelated key, which are used to identify and authenticate subscribers onmobile telephony devices (such as mobile phones and computers). It isalso possible to store contact information on many SIM cards.

The speaker 120 outputs sound-related results processed by the processor102. The microphone 122 receives sound-related inputs to be used by theprocessor 102.

FIGS. 6 and 7 show an example of protocol stacks in a 3GPP basedwireless communication system to which implementations of the presentdisclosure is applied.

In particular, FIG. 6 illustrates an example of a radio interface userplane protocol stack between a UE and a BS and FIG. 7 illustrates anexample of a radio interface control plane protocol stack between a UEand a BS. The control plane refers to a path through which controlmessages used to manage call by a UE and a network are transported. Theuser plane refers to a path through which data generated in anapplication layer, for example, voice data or Internet packet data aretransported. Referring to FIG. 6, the user plane protocol stack may bedivided into Layer 1 (i.e., a PHY layer) and Layer 2. Referring to FIG.7, the control plane protocol stack may be divided into Layer 1 (i.e., aPHY layer), Layer 2, Layer 3 (e.g., an RRC layer), and a non-accessstratum (NAS) layer. Layer 1, Layer 2 and Layer 3 are referred to as anaccess stratum (AS).

In the 3GPP LTE system, the Layer 2 is split into the followingsublayers: MAC, RLC, and PDCP. In the 3GPP NR system, the Layer 2 issplit into the following sublayers: MAC, RLC, PDCP and SDAP. The PHYlayer offers to the MAC sublayer transport channels, the MAC sublayeroffers to the RLC sublayer logical channels, the RLC sublayer offers tothe PDCP sublayer RLC channels, the PDCP sublayer offers to the SDAPsublayer radio bearers. The SDAP sublayer offers to 5G core networkquality of service (QoS) flows.

In the 3GPP NR system, the main services and functions of the MACsublayer include: mapping between logical channels and transportchannels; multiplexing/de-multiplexing of MAC SDUs belonging to one ordifferent logical channels into/from transport blocks (TB) deliveredto/from the physical layer on transport channels; scheduling informationreporting; error correction through hybrid automatic repeat request(HARQ) (one HARQ entity per cell in case of carrier aggregation (CA));priority handling between UEs by means of dynamic scheduling; priorityhandling between logical channels of one UE by means of logical channelprioritization; padding. A single MAC entity may support multiplenumerologies, transmission timings and cells. Mapping restrictions inlogical channel prioritization control which numerology(ies), cell(s),and transmission timing(s) a logical channel can use.

Different kinds of data transfer services are offered by MAC. Toaccommodate different kinds of data transfer services, multiple types oflogical channels are defined, i.e., each supporting transfer of aparticular type of information. Each logical channel type is defined bywhat type of information is transferred. Logical channels are classifiedinto two groups: control channels and traffic channels. Control channelsare used for the transfer of control plane information only, and trafficchannels are used for the transfer of user plane information only.Broadcast control channel (BCCH) is a downlink logical channel forbroadcasting system control information, paging control channel (PCCH)is a downlink logical channel that transfers paging information, systeminformation change notifications and indications of ongoing publicwarning service (PWS) broadcasts, common control channel (CCCH) is alogical channel for transmitting control information between UEs andnetwork and used for UEs having no RRC connection with the network, anddedicated control channel (DCCH) is a point-to-point bi-directionallogical channel that transmits dedicated control information between aUE and the network and used by UEs having an RRC connection. Dedicatedtraffic channel (DTCH) is a point-to-point logical channel, dedicated toone UE, for the transfer of user information. A DTCH can exist in bothuplink and downlink. In downlink, the following connections betweenlogical channels and transport channels exist: BCCH can be mapped tobroadcast channel (BCH); BCCH can be mapped to downlink shared channel(DL-SCH); PCCH can be mapped to paging channel (PCH); CCCH can be mappedto DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped toDL-SCH. In uplink, the following connections between logical channelsand transport channels exist: CCCH can be mapped to uplink sharedchannel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mappedto UL-SCH.

The RLC sublayer supports three transmission modes: transparent mode(TM), unacknowledged mode (UM), and acknowledged node (AM). The RLCconfiguration is per logical channel with no dependency on numerologiesand/or transmission durations. In the 3GPP NR system, the main servicesand functions of the RLC sublayer depend on the transmission mode andinclude: transfer of upper layer PDUs; sequence numbering independent ofthe one in PDCP (UM and AM); error correction through ARQ (AM only);segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs;reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDUdiscard (AM and UM); RLC re-establishment; protocol error detection (AMonly).

In the 3GPP NR system, the main services and functions of the PDCPsublayer for the user plane include: sequence numbering; headercompression and decompression using robust header compression (ROHC);transfer of user data; reordering and duplicate detection; in-orderdelivery; PDCP PDU routing (in case of split bearers); retransmission ofPDCP SDUs; ciphering, deciphering and integrity protection; PDCP SDUdiscard; PDCP re-establishment and data recovery for RLC AM; PDCP statusreporting for RLC AM; duplication of PDCP PDUs and duplicate discardindication to lower layers. The main services and functions of the PDCPsublayer for the control plane include: sequence numbering; ciphering,deciphering and integrity protection; transfer of control plane data;reordering and duplicate detection; in-order delivery; duplication ofPDCP PDUs and duplicate discard indication to lower layers.

In the 3GPP NR system, the main services and functions of SDAP include:mapping between a QoS flow and a data radio bearer; marking QoS flow ID(QFI) in both DL and UL packets. A single protocol entity of SDAP isconfigured for each individual PDU session.

In the 3GPP NR system, the main services and functions of the RRCsublayer include: broadcast of system information related to AS and NAS;paging initiated by 5GC or NG-RAN; establishment, maintenance andrelease of an RRC connection between the UE and NG-RAN; securityfunctions including key management; establishment, configuration,maintenance and release of signaling radio bearers (SRBs) and data radiobearers (DRBs); mobility functions (including: handover and contexttransfer, UE cell selection and reselection and control of cellselection and reselection, inter-RAT mobility); QoS managementfunctions; UE measurement reporting and control of the reporting;detection of and recovery from radio link failure; NAS message transferto/from NAS from/to UE.

FIG. 8 shows a frame structure in a 3GPP based wireless communicationsystem to which implementations of the present disclosure is applied.

The frame structure shown in FIG. 8 is purely exemplary and the numberof subframes, the number of slots, and/or the number of symbols in aframe may be variously changed. In the 3GPP based wireless communicationsystem, OFDM numerologies (e.g., subcarrier spacing (SCS), transmissiontime interval (TTI) duration) may be differently configured between aplurality of cells aggregated for one UE. For example, if a UE isconfigured with different SCSs for cells aggregated for the cell, an(absolute time) duration of a time resource (e.g., a subframe, a slot,or a TTI) including the same number of symbols may be different amongthe aggregated cells. Herein, symbols may include OFDM symbols (orCP-OFDM symbols), SC-FDMA symbols (or discrete Fouriertransform-spread-OFDM (DFT-s-OFDM) symbols).

Referring to FIG. 8, downlink and uplink transmissions are organizedinto frames. Each frame has T_(f)=10 ms duration. Each frame is dividedinto two half-frames, where each of the half-frames has 5 ms duration.Each half-frame consists of 5 subframes, where the duration T_(sf) persubframe is 1 ms. Each subframe is divided into slots and the number ofslots in a subframe depends on a subcarrier spacing. Each slot includes14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP,each slot includes 14 OFDM symbols and, in an extended CP, each slotincludes 12 OFDM symbols. The numerology is based on exponentiallyscalable subcarrier spacing Δf=2^(u)*15 kHz.

Table 1 shows the number of OFDM symbols per slot N^(slot) _(symb), thenumber of slots per frame N^(frame,u) _(slot), and the number of slotsper subframe N^(subframe,u) _(slot) for the normal CP, according to thesubcarrier spacing Δf=2^(u)*15 kHz.

TABLE 1 u N^(slot) _(symb) N^(frame, u) _(slot) N^(subframe, u) _(slot)0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

Table 2 shows the number of OFDM symbols per slot N^(slot) _(symb), thenumber of slots per frame N^(frame,u) _(slot), and the number of slotsper subframe N^(subframe,u) _(slot) for the extended CP, according tothe subcarrier spacing Δf=2^(u)*15 kHz.

TABLE 2 u N^(slot) _(symb) N^(frame, u) _(slot) N^(subframe, u) _(slot)2 12 40 4

A slot includes plural symbols (e.g., 14 or 12 symbols) in the timedomain. For each numerology (e.g., subcarrier spacing) and carrier, aresource grid of N^(size,u) _(grid,x)*N^(RB) _(sc) subcarriers andN^(subframe,u) _(symb) OFDM symbols is defined, starting at commonresource block (CRB) N^(start,u) _(grid) indicated by higher-layersignaling (e.g., RRC signaling), where N^(size,u) _(grid,x) is thenumber of resource blocks (RBs) in the resource grid and the subscript xis DL for downlink and UL for uplink. N^(RB) _(sc) is the number ofsubcarriers per RB. In the 3GPP based wireless communication system,N^(RB) _(sc) is 12 generally. There is one resource grid for a givenantenna port p, subcarrier spacing configuration u, and transmissiondirection (DL or UL). The carrier bandwidth N^(size,u) _(grid) forsubcarrier spacing configuration u is given by the higher-layerparameter (e.g., RRC parameter). Each element in the resource grid forthe antenna port p and the subcarrier spacing configuration u isreferred to as a resource element (RE) and one complex symbol may bemapped to each RE. Each RE in the resource grid is uniquely identifiedby an index k in the frequency domain and an index l representing asymbol location relative to a reference point in the time domain. In the3GPP based wireless communication system, an RB is defined by 12consecutive subcarriers in the frequency domain.

In the 3GPP NR system, RBs are classified into CRBs and physicalresource blocks (PRBs). CRBs are numbered from 0 and upwards in thefrequency domain for subcarrier spacing configuration u. The center ofsubcarrier 0 of CRB 0 for subcarrier spacing configuration u coincideswith ‘point A’ which serves as a common reference point for resourceblock grids. In the 3GPP NR system, PRBs are defined within a bandwidthpart (BWP) and numbered from 0 to N^(size) _(BWP,i)−1, where i is thenumber of the bandwidth part. The relation between the physical resourceblock n_(PRB) in the bandwidth part i and the common resource blockn_(CRB) is as follows: n_(PRB)=n_(CRB)+N^(size) _(BWP,i), where N^(size)_(BWP,i) is the common resource block where bandwidth part startsrelative to CRB 0. The BWP includes a plurality of consecutive RBs. Acarrier may include a maximum of N (e.g., 5) BWPs. A UE may beconfigured with one or more BWPs on a given component carrier. Only oneBWP among BWPs configured to the UE can active at a time. The active BWPdefines the UE's operating bandwidth within the cell's operatingbandwidth.

The NR frequency band may be defined as two types of frequency range,i.e., FR1 and FR2. The numerical value of the frequency range may bechanged. For example, the frequency ranges of the two types (FR1 andFR2) may be as shown in Table 3 below. For ease of explanation, in thefrequency ranges used in the NR system, FR1 may mean “sub 6 GHz range”,FR2 may mean “above 6 GHz range,” and may be referred to as millimeterwave (mmW).

TABLE 3 Frequency Range Corresponding designation frequency rangeSubcarrier Spacing FR1  450 MHz-6000 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As mentioned above, the numerical value of the frequency range of the NRsystem may be changed. For example, FR1 may include a frequency band of410 MHz to 7125 MHz as shown in Table 4 below. That is, FR1 may includea frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. Forexample, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) ormore included in FR1 may include an unlicensed band. Unlicensed bandsmay be used for a variety of purposes, for example for communication forvehicles (e.g., autonomous driving).

TABLE 4 Frequency Range Corresponding designation frequency rangeSubcarrier Spacing FR1  410 MHz-7125 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

In the present disclosure, the term “cell” may refer to a geographicarea to which one or more nodes provide a communication system, or referto radio resources. A “cell” as a geographic area may be understood ascoverage within which a node can provide service using a carrier and a“cell” as radio resources (e.g., time-frequency resources) is associatedwith bandwidth which is a frequency range configured by the carrier. The“cell” associated with the radio resources is defined by a combinationof downlink resources and uplink resources, for example, a combinationof a DL component carrier (CC) and a UL CC. The cell may be configuredby downlink resources only, or may be configured by downlink resourcesand uplink resources. Since DL coverage, which is a range within whichthe node is capable of transmitting a valid signal, and UL coverage,which is a range within which the node is capable of receiving the validsignal from the UE, depends upon a carrier carrying the signal, thecoverage of the node may be associated with coverage of the “cell” ofradio resources used by the node. Accordingly, the term “cell” may beused to represent service coverage of the node sometimes, radioresources at other times, or a range that signals using the radioresources can reach with valid strength at other times.

In CA, two or more CCs are aggregated. A UE may simultaneously receiveor transmit on one or multiple CCs depending on its capabilities. CA issupported for both contiguous and non-contiguous CCs. When CA isconfigured, the UE only has one RRC connection with the network. At RRCconnection establishment/re-establishment/handover, one serving cellprovides the NAS mobility information, and at RRC connectionre-establishment/handover, one serving cell provides the security input.This cell is referred to as the primary cell (PCell). The PCell is acell, operating on the primary frequency, in which the UE eitherperforms the initial connection establishment procedure or initiates theconnection re-establishment procedure. Depending on UE capabilities,secondary cells (SCells) can be configured to form together with thePCell a set of serving cells. An SCell is a cell providing additionalradio resources on top of special cell (SpCell). The configured set ofserving cells for a UE therefore always consists of one PCell and one ormore SCells. For dual connectivity (DC) operation, the term SpCellrefers to the PCell of the master cell group (MCG) or the primary SCell(PSCell) of the secondary cell group (SCG). An SpCell supports PUCCHtransmission and contention-based random access, and is alwaysactivated. The MCG is a group of serving cells associated with a masternode, comprised of the SpCell (PCell) and optionally one or more SCells.The SCG is the subset of serving cells associated with a secondary node,comprised of the PSCell and zero or more SCells, for a UE configuredwith DC. For a UE in RRC_CONNECTED not configured with CA/DC, there isonly one serving cell comprised of the PCell. For a UE in RRC_CONNECTEDconfigured with CA/DC, the term “serving cells” is used to denote theset of cells comprised of the SpCell(s) and all SCells. In DC, two MACentities are configured in a UE: one for the MCG and one for the SCG.

FIG. 9 shows a data flow example in the 3GPP NR system to whichimplementations of the present disclosure is applied.

Referring to FIG. 9, “RB” denotes a radio bearer, and “H” denotes aheader. Radio bearers are categorized into two groups: DRBs for userplane data and SRBs for control plane data. The MAC PDU istransmitted/received using radio resources through the PHY layer to/froman external device. The MAC PDU arrives to the PHY layer in the form ofa transport block.

In the PHY layer, the uplink transport channels UL-SCH and RACH aremapped to their physical channels physical uplink shared channel (PUSCH)and physical random access channel (PRACH), respectively, and thedownlink transport channels DL-SCH, BCH and PCH are mapped to physicaldownlink shared channel (PDSCH), physical broadcast channel (PBCH) andPDSCH, respectively. In the PHY layer, uplink control information (UCI)is mapped to physical uplink control channel (PUCCH), and downlinkcontrol information (DCI) is mapped to physical downlink control channel(PDCCH). A MAC PDU related to UL-SCH is transmitted by a UE via a PUSCHbased on an UL grant, and a MAC PDU related to DL-SCH is transmitted bya BS via a PDSCH based on a DL assignment.

Support for vehicle-to-vehicle (V2V) and vehicle-to-everything (V2X)services has been introduced in LTE during Releases 14 and 15, in orderto expand the 3GPP platform to the automotive industry. These work itemsdefined an LTE sidelink suitable for vehicular applications, andcomplementary enhancements to the cellular infrastructure.

Further to this work, requirements for support of enhanced V2X use caseshave been defined in 5G LTE/NR, which are broadly arranged into four usecase groups:

1) Vehicles platooning enables the vehicles to dynamically form aplatoon travelling together. All the vehicles in the platoon obtaininformation from the leading vehicle to manage this platoon. Theseinformation allow the vehicles to drive closer than normal in acoordinated manner, going to the same direction and travelling together.

2) Extended Sensors enables the exchange of raw or processed datagathered through local sensors or live video images among vehicles, roadsite units, devices of pedestrian and V2X application servers. Thevehicles can increase the perception of their environment beyond of whattheir own sensors can detect and have a more broad and holistic view ofthe local situation. High data rate is one of the key characteristics.

3) Advanced driving enables semi-automated or full-automated driving.Each vehicle and/or RSU shares its own perception data obtained from itslocal sensors with vehicles in proximity and that allows vehicles tosynchronize and coordinate their trajectories or maneuvers. Each vehicleshares its driving intention with vehicles in proximity too.

4) Remote driving enables a remote driver or a V2X application tooperate a remote vehicle for those passengers who cannot drive bythemselves or remote vehicles located in dangerous environments. For acase where variation is limited and routes are predictable, such aspublic transportation, driving based on cloud computing can be used.High reliability and low latency are the main requirements.

NR sidelink (SL) unicast, groupcast, and broadcast design is described.SL broadcast, groupcast, and unicast transmissions are supported for thein-coverage, out-of-coverage and partial-coverage scenarios.

FIGS. 10 and 11 show an example of PC5 protocol stacks to whichimplementations of the present disclosure is applied.

FIG. 10 illustrates an example of a PC5 control plane (PC5-C) protocolstack between UEs. The AS protocol stack for the control plane in thePC5 interface consists of at least RRC, PDCP, RLC and MAC sublayers, andthe physical layer.

FIG. 11 illustrates an example of a PC5 user plane (PC5-U) protocolstack between UEs. The AS protocol stack for user plane in the PC5interface consists of at least PDCP, RLC and MAC sublayers, and thephysical layer.

For the purposes of physical layer analysis, it is assumed that higherlayers decide if unicast, groupcast, or broadcast transmission is to beused for a particular data transfer, and they correspondingly inform thephysical layer. When considering a unicast or groupcast transmission, itis assumed that the UE is able to establish which unicast or groupcastsession a transmission belongs to, and that the following identities isknown to the physical layer:

-   -   The layer-1 destination ID, conveyed via physical sidelink        control channel (PSCCH)    -   Additional layer-1 ID(s), conveyed via PSCCH, at least for the        purpose of identifying which transmissions can be combined in        reception when HARQ feedback is in use    -   HARQ process ID

For the purpose of Layer 2 analysis, it is assumed that upper layers(i.e., above AS) provide the information on whether it is a unicast,groupcast or broadcast transmission for a particular data transfer. Forthe unicast and groupcast transmission in SL, the following identitiesis known to Layer 2:

-   -   Unicast: destination ID, source ID    -   Groupcast: destination group ID, source ID

Discovery procedure and related messages for the unicast and groupcasttransmission are up to upper layers.

At least the following two SL resource allocation modes are defined asfollows.

(1) Mode 1: BS schedules SL resource(s) to be used by UE for SLtransmission(s).

(2) Mode 2: UE determines, i.e., BS does not schedule, SL transmissionresource(s) within SL resources configured by BS/network orpre-configured SL resources.

The definition of SL resource allocation Mode 2 covers:

a) UE autonomously selects SL resource for transmission

b) UE assists SL resource selection for other UE(s)

c) UE is configured with NR configured grant (Type-1 like) for SLtransmission

d) UE schedules SL transmissions of other UEs

For SL resource allocation Mode 2, sensing and resource(re-)selection-related procedures may be considered. The sensingprocedure considered is defined as decoding sidelink control information(SCI) from other UEs and/or SL measurements. The resource (re-)selectionprocedure considered uses the results of the sensing procedure todetermine resource(s) for SL transmission.

For Mode 2(a), SL sensing and resource selection procedures may beconsidered in the context of a semi-persistent scheme where resource(s)are selected for multiple transmissions of different TBs and a dynamicscheme where resource(s) are selected for each TB transmission.

The following techniques may be considered to identify occupied SLresources:

-   -   Decoding of SL control channel transmissions    -   SL measurements    -   Detection of SL transmissions

The following aspects may be considered for SL resource selection:

-   -   How a UE selects resource for PSCCH and physical sidelink shared        channel (PSSCH) transmission (and other SL physical        channel/signals that are defined)    -   Which information is used by UE for resource selection procedure

Mode 2(b) is a functionality that can be part of Mode 2(a), (c), (d)operation.

For out-of-coverage operation, Mode 2(c) assumes a (pre-)configurationof single or multiple SL transmission patterns, defined on each SLresource pool. For in-coverage operation, Mode 2(c) assumes that gNBconfiguration indicates single or multiple SL transmission patterns,defined on each SL resource pool. If there is a single patternconfigured to a transmitting UE, there is no sensing procedure executedby UE, while if multiple patterns are configured, there is a possibilityof a sensing procedure.

A pattern is defined by the size and position(s) of the resource in timeand frequency, and the number of resources.

For Mode 2(d), the procedures to become or serve as a scheduling UE forin-coverage and out-of-coverage scenarios may be considered as follows:

-   -   Scheduling UE is configured by gNB    -   Application layer or pre-configuration selects scheduling UE    -   Receiver UE schedules transmissions of the transmitter UE during        the session    -   Scheduling UE is decided by multiple UEs including the one that        is finally selected.

The UE may autonomously decide to serve as a scheduling UE/offerscheduling UE functions (i.e., by self-nomination).

In NR V2X, one wireless device may establish a PC5 link (e.g.,one-to-one connection and/or session between wireless devices) forunicast service with another wireless device. PC5 Signaling protocolabove RRC layer in the wireless devices may be used for unicast linkestablishment and management. Based on the unicast link establishmentand management, the wireless devices may exchange PC5 signaling (i.e.,upper layer signaling than RRC signaling) to successfully orunsuccessfully establish a unicast link with security activation orrelease the established unicast link.

FIG. 12 shows an example of PC5 link setup to which implementations ofthe present disclosure is applied.

Referring to FIG. 12, an initiating UE transmits a direct communicationrequest message to a target UE for PC5 link setup. Upon transmitting thedirect communication request message, the timer T4100 may start. Uponreceiving the direct communication request message from the initiatingUE, the target UE transmits a direct communication accept message to theinitiating UE in response to the direct communication request message.Upon transmitting the direct communication accept message, the timerT4108 may start. Upon receiving the direct communication accept messagefrom the target UE, PC5 link can be established successfully, upon whichthe timer T4100 may stop.

Alternatively, referring to FIG. 12, an initiating UE transmits a directcommunication request message to a target UE for PC5 link setup. Upontransmitting the direct communication request message, the timer T4100may start. Upon receiving the direct communication request message fromthe initiating UE, the target UE transmits a direct communication rejectmessage to the initiating UE in response to the direct communicationrequest message. Upon receiving the direct communication reject messagefrom the target UE, PC5 link setup procedure may stop, upon which thetimer T4100 may stop.

FIG. 13 shows an example of security mode control to whichimplementations of the present disclosure is applied.

Referring to FIG. 13, a commanding UE transmits a direct security modecommand message to a peer UE for security mode control. Upontransmitting the direct security mode command message, the timer T4111may start. Upon receiving the direct security mode command message fromthe commanding UE, the peer UE transmits a direct security mode completemessage to the commanding UE in response to the direct security modecommand message. Upon receiving the direct security mode completemessage from the peer UE, security mode can be controlled successfully,upon which the timer T4111 may stop.

Alternatively, referring to FIG. 13, a commanding UE transmits a directsecurity mode command message to a peer UE for security mode control.Upon transmitting the direct security mode command message, the timerT4111 may start. Upon receiving the direct security mode command messagefrom the commanding UE, the peer UE transmits a direct security modereject message to the commanding UE in response to the direct securitymode command message. Upon receiving the direct security mode rejectmessage from the peer UE, security mode control procedure may stop, uponwhich the timer T4111 may stop.

FIG. 14 shows an example of PC5 link release to which implementations ofthe present disclosure is applied.

Referring to FIG. 14, a releasing UE transmits a direct communicationrelease message to a peer UE for PC5 link release. Upon transmitting thedirect communication release message, the timer T4103 may start. Uponreceiving the direct communication release message from the releasingUE, the peer UE transmits a direct communication release accept messageto the releasing UE in response to the direct communication releasemessage. Upon receiving the direct communication release accept messagefrom the peer UE, PC5 link can be released successfully, upon which thetimer T4103 may stop.

FIG. 15 shows an example of direct link keepalive procedure to whichimplementations of the present disclosure is applied.

The direct link keepalive procedure is used to maintain the direct linkbetween two proximity-based services (ProSe)-enabled UEs, i.e., checkthat the link between the two UEs is still viable. The procedure can beinitiated by only one UE or both of the UEs in the established directlink. If the direct link is used for one-to-one communication between aremote UE and a ProSe UE-to-network relay UE, only the remote UE shallinitiate the link keepalive procedure.

In this procedure, the UE sending the DIRECT_COMMUNICATION_KEEPALIVEmessage is called the “requesting UE” and the other UE is called the“peer UE”.

The requesting UE manages a keepalive timer T4102 and a keepalivecounter for this procedure. The keepalive timer T4102 is used to triggerthe periodic initiation of the procedure. It is started or restartedwhenever the UE receives a PC5 Signalling message or PC5 user plane datafrom the peer UE over this link. The keepalive counter is set to aninitial value of zero after link establishment.

The requesting UE may initiate the procedure if:

-   -   a request from upper layers to check the viability of the direct        link is received; or    -   the keepalive timer T4102 for this link expires.

The requesting UE initiates the procedure by stopping timer T4102 if itis still running and generating a DIRECT_COMMUNICATION_KEEPALIVE messagewith a Keepalive counter information element (IE) that contains thevalue of the keepalive counter for this link. Optionally, the initiatingUE may include a maximum inactivity period IE to indicate the maximuminactivity period of the requesting UE over this direct link. When aremote UE sends DIRECT_COMMUNICATION_KEEPALIVE message to the ProSeUE-to-network relay UE, this IE shall be included.

After the DIRECT_COMMUNICATION_KEEPALIVE message is generated, therequesting UE shall pass this message to the lower layers fortransmission along with the requesting UE's Layer 2 ID (for unicastcommunication) and the peer UE's Layer 2 ID (for unicast communication),and start retransmission timer T4101.

Upon receiving a DIRECT_COMMUNICATION_KEEPALIVE message, the peer UEshall respond with a DIRECT_COMMUNICATION_KEEPALIVE_ACK messageincluding the Keepalive Counter IE set to the same value as thatreceived in the DIRECT_COMMUNICATION_KEEPALIVE message.

If a maximum inactivity period IE is included in theDIRECT_COMMUNICATION_KEEPALIVE message, the peer UE shall stop theinactivity timer T4108 if it is running, and restart the timer T4108with the value provided in the IE, If any communication activity occursin this direct link before the timer T4108 expires, the UE shall stopthe timer T4108 and reset it with the initial value.

Upon receiving a DIRECT_COMMUNICATION_KEEPALIVE_ACK message, therequesting UE shall stop retransmission timer T4101, start keepalivetimer T4102 and increment the keepalive counter for this link.

One of key issue in NR V2X (or, enhanced V2X (eV2X)) is QoS support overUu interface. To address this issue, twofold solution may be introduced.In its first part, it is addressed if any new QoS characteristics for Uuinterface are needed, while in the second part it is addressed if newstandardized 5G QoS identifier (5QI) values are needed.

eV2X is a distinctive family of services which may cover ultra-reliableand low latency scenarios, while at the same time it may require highdata rates. Service requirements to enhance 3GPP support for V2Xscenarios in the 3GPP systems were specified. Requirements includesupport for both safety and non-safety V2X scenarios:

-   -   Safety-related V2X scenarios: e.g. automated driving, vehicle        platooning, etc.;    -   Non-safety-related V2X scenarios: e.g., mobile high data rate        entertainment, mobile hotspot/office/home, dynamic digital map        update etc.

Notably, categories of requirements (CoR) are defined to support eV2Xscenarios. Five CoRs are defined: general aspects, vehicle platooning,advanced driving, extended sensors and remote driving.

Additionally, the concept of level of automation (LoA) is defined, whichreflects the functional aspects of the technology and affects the systemperformance requirements. The defined LoAs are: no automation (0),driver assistance (1), partial automation (2), conditional automation(3), high Automation (4), full Automation (5).

For each CoR and each LoA, performance requirements are specified interms of:

-   -   Payload (Bytes);    -   Transmission rate (Message/Sec);    -   Maximum end-to-end latency (ms);    -   Reliability (%);    -   Data rate (Mbps);    -   Minimum required communication range (meters).

The above requirements are covered by the 5G QoS characteristicsassociated with 5QI.

-   -   The Payload can be linked to the maximum data burst volume        (which can be defined to be equal to the maximum required        payload for the CoR & LoA+ protocol overhead),    -   the Maximum end-to-end latency (ms) is similar to the packet        delay budget (PDB), while the reliability is calculated by using        jointly the PDB and the packet error rate (PER). Precisely,        reliability (%) is defined as the success probability of        transmitting X byte within a certain delay, which is the time it        takes to deliver a small data packet from the radio protocol        layer 2/3 SDU ingress point to the radio protocol layer 2/3 SDU        egress point of the radio interface.    -   The data rate is equal to the guaranteed flow bit rate        (guaranteed bit rate (GBR) QoS flows) or the non-guaranteed bit        rate (non-GBR). The minimum required communication range is not        considered as QoS characteristics.

Consequently, referring to V2X communication over Uu, no new QoScharacteristics on top of those already defined are necessary.

The procedures for the establishment and maintenance of secure L2 linkover PC5 may be enhanced and adapted for the V2X use, subject to thedecisions above regarding signalling protocol choice, security handling,etc.

Some addition considerations for the V2X for the link/group handling isrequired though. For V2X communication, not all UEs will be supportingor use unicast communication. In addition, not all services may be runover the same channel or RAT (e.g. LTE V2X vs. NR V2X). With V2X, thereis no discovery channel like that of ProSe (i.e., PC5-D), and there isno assumption on the configuration from network as that of public safetyuse. Therefore, in order to support the link establishment, there is aneed for service announcement in order to inform the peer of theexistence of the UE and the capability of the UE for the unicastcommunication, e.g., channel to operate, or the services supported, etc.

Such a service announcement should be made accessible to all the UEsthat are interested in using the service. For example, such announcementcould be either configured to send over a dedicate channel, similar tohow WAVE service advertisement (WSA) is handled, or to be piggybacked onthe periodical messages from the supporting UEs.

For layer 2 link maintenance, keep-alive functionality is needed todetect that when the UEs are not in direct communication range, so thatthey can proceed with implicit layer 2 link release.

FIG. 16 shows an example of UE oriented layer 2 link establishmentprocedure to which implementations of the present disclosure is applied.

In step S1600, the UE-1 may send the Direct Communication Requestmessage with broadcast mechanism, i.e., to a broadcast addressassociated with the application instead of the L2 ID of UE-2. The upperidentifier of UE-2 is included in the Direct Communication Requestmessage to allow UE-2 to decide on if to respond to the request. TheSource L2 ID of this message should be the unicast L2 ID of the UE-1.

The Direct Communication Request message should be transmitted usingdefault AS layer setting, e.g., broadcast setting, that can beunderstood by UE-2.

In step S1610, UE-2 uses the source L2 ID of the received DirectCommunication Request message as destination L2 ID in the subsequentsignalling to UE-1, and uses its own unicast L2 ID as the source L2 ID.UE-1 obtains UE-2's L2 ID for future communication, for signaling anddata traffic.

FIG. 17 shows an example of V2X service oriented layer 2 linkestablishment procedure to which implementations of the presentdisclosure is applied.

In step S1700, the UE-1 may send the Direct Communication Requestmessage. The information about V2X service requesting L2 linkestablishment, i.e., information about the announced V2X service, isincluded in the Direct Communication Request message to allow other UEsto decide on if to respond to the request.

In step S1710, the UEs that are interested in using the V2X serviceannounced by the Direct Communication Request message can respond to therequest (e.g., UE-2 and UE-4 in FIG. 16).

After establishing layer 2 link with other UE(s) as described above, newUE(s) can enter proximity with UE-1, i.e., UE-1's direct communicationrange. In this case, UE-1 may initiate V2X service oriented layer 2 linkestablishment procedure as it is aware of new UE(s) from applicationlayer messages sent by the UE(s). Or, the new UE may initiate V2Xservice oriented layer 2 link establishment procedure. Therefore, UE-1does not have to keep sending a Direct Communication Request messageperiodically to announce the V2X service it wants to establish L2 linkwith other UE for unicast.

The layer 2 link supports the non-IP traffic. No IP address negotiationand allocation procedure would be carried out.

One of key issue in NR V2X (or, eV2X) is QoS support over PC5 interface.The QoS requirements for eV2X are different from that of the evolvedpacket system (EPS) V2X, and the previous defined ProSe-per-packetpriority (PPPP)/ProSe-per-packet reliability (PPPR) are considered notto satisfy the needs. Specifically, there are much more QoS parametersto consider for the eV2X services.

To address this issue, to use 5QI for eV2X communication over PC5interface may be introduced. This allows a unified QoS model for eV2Xservices over different links. Since the same set of servicerequirements apply to both PC5 based V2X communication and Uu based V2Xcommunication, these QoS characteristics could be well represented with5QI, and it is therefore possible to have a unified QoS model for PC5and Uu, i.e., also use 5QIs for V2X communication over PC5, such thatthe application layer can have a consistent way of indicating QoSrequirements regardless of the link used. This does not prevent the ASlayer from implementing different mechanisms over PC5 and Uu to achievethe QoS requirements.

Considering the 5GS V2X capable UEs, there are three different types oftraffic: broadcast, multicast, and unicast.

The UE-PC5-aggregate maximum bit rate (AMBR) is applied to all types oftraffic and is used for the RAN for capping the UE PC5 transmission inthe resources management.

For unicast type of traffic, it is clear that the same QoS model as thatof Uu can be utilized, i.e., each of the unicast link could be treatedas a bearer, and QoS flows could be associated with it. All the QoScharacteristics defined in 5QI and the additional parameter of data ratecould apply. In addition, the minimum required communication range couldbe treated as an additional parameter specifically for PC5 use.

For broadcast traffic, there is no bearer concept. Therefore, each ofthe message may have different characteristics according to theapplication requirements. The 5QI should then be used in the similarmanner as that of the PPPP/PPPR, i.e., to be tagged with each of thepacket. 5QI is able to represent all the characteristics needed for thePC5 broadcast operation, e.g., latency, priority, reliability, etc. Agroup of V2X broadcast specific 5QIs (i.e., V2X Qos class identifiers(VQIs)) could be defined for PC5 use.

UEs supporting sidelink communication can perform sidelink transmissionand reception. As mentioned above in FIG. 15, direct link keepaliveprocedure may be used to maintain the direct link between two UEsperforming sidelink communication. During certain time, if there is nosignaling or data on the established sidelink (i.e., expiry of T4102),UE shall perform direct link keepalive procedure to check availabilityof the established sidelink link. If there is no keepaliveacknowledgement message during certain time, UE performs direct linkrelease procedure.

Currently, there is no procedure to support a minimum requiredcommunication range. As simple solution, it can be considered that UEperforms direct link release procedure as soon as UE goes out of minimumrequired communication range. However, it can cause unnecessarysignaling overhead considering that UE may go into minimum requiredcommunication range within short time. If the sidelink connection isreleased, when the UE goes into the minimum required communicationrange, the UE may perform procedures required for sidelink communicationagain (e.g., to setup the sidelink communication, negotiate QoS level,etc.)

According to implementations of the present disclosure, when aninitiating/detecting wireless device performing unicast and/or groupcastsidelink communication having minimum required communication rangedetects that the initiating/detecting wireless device is not in theminimum required communication range, the initiating/detecting wirelessdevice may suspend radio bearers and/or context for the sidelinkcommunication. The initiating/detecting wireless device may inform apeer/target wireless device that the initiating/detecting wirelessdevice is not in the minimum required communication range.

According to implementations of the present disclosure, upon receivingthe information that the initiating/detecting wireless device is not inthe minimum required communication range, the peer/target wirelessdevice may stop data and signaling transmission to theinitiating/detecting wireless device via the established sidelinkconnection (and/or session), except for signaling to enable theinitiating/detecting wireless device to identity whether or not theinitiating/detecting wireless device is in the minimum requiredcommunication range. But, the peer/target wireless device may holdcontexts of the initiating/detecting wireless device.

According to implementations of the present disclosure, if theinitiating/detecting wireless device detects within certain time thatthe initiating/detecting wireless device is in the minimum requiredcommunication range, the initiating/detecting wireless device may informthe peer/target wireless device that the initiating/detecting wirelessdevice is in the minimum required communication range again. Uponreceiving the information that the initiating/detecting wireless deviceis in the minimum required communication range again, the peer/targetwireless device may resume data and signaling transmission to theinitiating/detecting wireless device via the established sidelinkconnection (and/or session).

According to implementations of the present disclosure, if theinitiating/detecting wireless device does not detect within the certaintime that the initiating/detecting wireless device is in the minimumrequired communication range, the initiating/detecting wireless devicemay perform direct communication release procedure. If the peer/targetwireless device does not receive the information that theinitiating/detecting wireless device is in the minimum requiredcommunication range within the certain time, the peer/target wirelessdevice may perform direct communication release procedure.

According to implementations of the present disclosure, it may beassumed that wireless devices are performing unicast sidelinkcommunication and/or group(cast) sidelink communication between wirelessdevices. One-to-one sidelink connection may be established or may not beestablished between wireless device.

According to implementations of the present disclosure, it may beassumed that the wireless device has a minimum required communicationrange for the unicast and/or group(cast) sidelink communication.

The following drawings are created to explain specific embodiments ofthe present disclosure. The names of the specific devices or the namesof the specific signals/messages/fields shown in the drawings areprovided by way of example, and thus the technical features of thepresent disclosure are not limited to the specific names used in thefollowing drawings.

FIG. 18 shows an example of a method for a first wireless device towhich implementations of the present disclosure is applied.

In some implementations, the first wireless device is a peer wirelessdevice of a second wireless device which detects out of a minimumrequired communication range. The first wireless device may be incommunication with at least one of a mobile device, a network, and/orautonomous vehicles other than the first wireless device.

In step S1800, the first wireless device performs a transmission withthe second wireless device.

In some implementations, the transmission with the second wirelessdevice may include at least one of a unicast sidelink communicationand/or a groupcast sidelink communication. The minimum requiredcommunication range may be for the unicast sidelink communication and/orfor the groupcast sidelink communication.

In step S1810, the first wireless device detects that the secondwireless device is out of a minimum required communication range.

In some implementations, that the second wireless device is out of theminimum required communication range may be detected by receiving, fromthe second wireless device, information that that the second wirelessdevice is out of the minimum required communication range.

In step S1820, the first wireless device suspends the transmission withthe second wireless device.

In some implementations, the transmission with the second wirelessdevice may be suspended except for signaling to enable the secondwireless device to identity whether or not the second wireless device isin the minimum required communication range.

In some implementations, a radio bearer related to the minimum requiredcommunication range may be suspended.

In some implementations, contexts of the second wireless device may beheld (e.g., not suspended) upon suspending the transmission with thesecond wireless device.

In some implementations, information for suspension of the transmissionwith the second wireless device may be transmitted to the secondwireless device.

In some implementations, a timer may start upon detecting that thesecond wireless device is out of the minimum required communicationrange. The transmission with the second wireless device may be resumedupon detecting that the second wireless device is in the minimumrequired communication range before expiry of the timer. That the secondwireless device is in the minimum required communication range may bedetected by receiving, from the second wireless device, information thatthat the second wireless device is in the minimum required communicationrange. Alternatively, the transmission with the second wireless devicemay be released upon expiry of the timer.

FIG. 19 shows an example of a method for establishing a connection by aninitiating/detecting wireless device to which implementations of thepresent disclosure is applied.

In this example, the initiating/detecting wireless device may be simplycalled an initiating wireless device, and a peer/target wireless devicemay be simply called a target wireless device.

In step S1900, the initiating wireless device performing unicastsidelink communication and/or groupcast sidelink communicationchecks/detects whether or not the initiating wireless device is in theminimum required communication range.

In some implementations, the detection may be performed by signaling ordata transmitted from the target wireless device. The detection may beachieved by signaling strength and/or quality (e.g., reference signalreceived power (RSRP) and/or reference signal received quality (RSRQ))for the sidelink between wireless devices.

In some implementations, the wireless devices performing the detectionmay be pre-determined and/or determined by sidelink signaling. Thewireless devices performing the detection may be group member. Thetarget wireless device may be group manager if there is a group manager(i.e., head wireless device) and group member(s) in unicast sidelinkcommunication and/or groupcast sidelink communication.

In step S1910, if the initiating wireless device detects that theinitiating wireless device goes out of the minimum requiredcommunication range, the initiating wireless device performs at leastone of the followings.

a) Send the message to the target wireless device to inform that thatthe initiating wireless device is not in the minimum requiredcommunication range;

In some implementations, the initiating wireless device may additionallyprovide current distance from the target wireless device. The distancemay be replaced with signaling strength and/or quality (e.g., RSRPand/or RSRQ) for the sidelink between the initiating wireless device andthe target wireless device.

In some implementations, the message may be to request suspendingsidelink communication. The message may include Direct CommunicationRelease message, Direct Communication Keepalive message, or a newmessage.

In some implementations, the message may include a cause informing ‘outof the minimum required communication range’. The cause may also beprovided to the upper layer.

b) Suspend transmission signaling and/or data to the target wirelessdevice;

c) Consider context related to the target wireless device as temporarilyinvalid and/or suspend;

In some implementations, context of the target wireless device and/orcontexts for the sidelink communication with the target wireless devicemay be considered as temporarily invalid and/or suspended. Forsuspending contexts, the initiating wireless device may perform tosuspend those contexts.

d) Set a timer Txxx with provided timer value and start the timer

In some implementations, the timer Txxx and timer value may be(pre-)configured and/or provided during one-to-one (sidelink) connectionestablishment and/or via broadcast manner.

In some implementations, if the initiating wireless device receives aresponse message from the target wireless device and the responsemessage includes information for the minimum required communicationrange which is updated with new value which is longer than currentdistance from the target wireless device, the initiating wireless devicemay continue to perform sidelink communication with the target wirelessdevice (s) by performing at least one of the followings.

a) Stop the timer Txxx and resume transmission signaling and/or data,which was suspended, to the target wireless device;

b) Consider context related to the target wireless device as validand/or active;

c) Apply the increased value to sidelink transmission and/or receptionif the response message includes information for increased value oftransmission power by the target wireless device and/or the initiatingwireless device;

d) Continue to perform sidelink communication with the target wirelessdevice.

The response message may be to resume for sidelink communication.

In some implementations, before expiry of the timer Txxx, if theinitiating wireless device goes into within the minimum requiredcommunication range, the initiating wireless device may continue toperform sidelink communication with the target wireless device byperforming at least one of the followings.

a) Send a message to request resuming sidelink communication;

In some implementations, the message may be to request resuming sidelinkcommunication. The message may include Direct Communication Releasemessage, Direct Communication Keepalive message, or a new message.

In some implementations, the message may include a cause informing‘going into the minimum required communication range’. The cause mayalso be provided to the upper layer.

b) Stop the timer Txxx and resume transmission signaling and/or data,which was suspended, to the target wireless device;

c) Consider context related to the target wireless device as validand/or active;

d) Continue to perform sidelink communication with the target wirelessdevice.

To perform b) to d), the initiating wireless device may need a responsemessage for the message sent in a) from the target wireless device.

In some implementations, if the timer Txxx expires in the initiatingwireless device (i.e., the initiating wireless device still stays out ofthe minimum required communication range until expiry of the timerTxxx), the initiating wireless device may perform direct link releaseprocedure for the target wireless device.

In some implementations, the direct link release procedure may beperformed implicitly or explicitly.

In some implementations, the release cause may be ‘out of the minimumrequired communication range’. The release cause may be provided toupper layer and/or the target wireless device.

FIG. 20 shows an example of a method for establishing a connection by apeer/target wireless device to which implementations of the presentdisclosure is applied.

In this example, the peer/target wireless device may be simply called atarget wireless device, and an initiating/detecting wireless device maybe simply called an initiating wireless device.

In step S2000, upon receiving a message informing that the initiatingwireless device it out of the minimum required communication range frominitiating wireless device, the target wireless device determineswhether or not continue sidelink communication with the initiatingwireless device.

In some implementations, the message may be to request suspendingsidelink communication. The message may include Direct CommunicationRelease message, Direct Communication Keepalive message, or a newmessage.

In some implementations, the message may include a cause informing ‘outof the minimum required communication range’. The cause may also beprovided to the upper layer.

In step S2010, upon determining to continue sidelink communication withthe initiating wireless device, the target wireless device sendsresponse message including an updated minimum required communicationrange with new value which is longer than current distance from thetarget wireless device to the initiating wireless device.

In some implementations, to support sidelink communication in theupdated minimum required communication range, the target wireless devicemay provide value of increased power to the initiating wireless device.

In some implementations, the response message may be to request resumingsidelink communication. The message may include Direct CommunicationRelease Reject message, Direct Communication Keepalive Accept message,or a new message.

In some implementations, the message may include a cause informing‘updated minimum required communication range’. The cause may also beprovided to the upper layer.

In step S2020, upon determining not to continue sidelink communicationwith the initiating wireless device and to wait the initiating wirelessdevice goes into within the minimum required communication range, thetarget wireless device performs at least one of the followings;

a) Stop/suspend transmission signaling and data to the initiatingwireless device, except for signaling to enable the initiating wirelessdevice to identify whether or not the initiating wireless device is inthe minimum required communication range;

b) Consider context related to the initiating wireless device astemporarily invalid and/or suspend;

In some implementations, context of the initiating wireless deviceand/or contexts for the sidelink communication with the initiatingwireless device may be considered as temporarily invalid and/orsuspended. For suspending contexts, the target wireless device mayperform to suspend those contexts.

c) Set a timer Txxx with provided timer value and start the timer

In some implementations, the timer Txxx and timer value may be(pre-)configured and/or provided during one-to-one (sidelink) connectionestablishment and/or via broadcast manner to group members.

d) Send a response message to inform that the target wireless devicedecides not to continue sidelink communication with the initiatingwireless device to the initiating wireless device;

In some implementations, the response message may be to confirmsuspending sidelink communication. The message may include DirectCommunication Release Accept message, Direct Communication KeepaliveAccept message, or a new message.

In some implementations, the response message may include suspendindication and/or configuration for sidelink communication.

In some implementations, the response message may include a causeinforming ‘out of the minimum required communication range’. The causemay also be provided to the upper layer.

In some implementations, before expiry of the timer Txxx, if the targetwireless device receives a message with information from the initiatingwireless device that the initiating wireless device goes into theminimum required communication range, the target wireless deviceperforms at least one of the followings:

a) Resume transmission signaling and/or data, which was suspended, tothe initiating wireless device;

b) Consider context related to the initiating wireless device as validand/or active;

c) Stop the timer Txxx

d) Send a response message to the initiating wireless device

In some implementations, the response message may include a resumemessage (or indication or configuration) for sidelink communication.

In some implementations, if the timer Txxx expires, (i.e., theinitiating wireless device still stays out of the minimum requiredcommunication range until expiry of the timer Txxx), the target wirelessdevice may perform direct link release procedure for the initiatingwireless device.

In some implementations, the direct link release procedure may beperformed implicitly or explicitly.

In some implementations, the release cause may be ‘out of the minimumrequired communication range’. The release cause may be provided toupper layer and/or the initiating wireless device.

In step S2030, upon determining not to continue sidelink communicationwith the initiating wireless device and not to wait the initiatingwireless device goes into within the minimum required communicationrange, the target wireless device performs direct link release procedurefor the initiating wireless device.

In some implementations, the direct link release procedure may beperformed implicitly or explicitly.

In some implementations, the release cause may be ‘out of the minimumrequired communication range’. The release cause may be provided toupper layer and/or the initiating wireless device.

In some implementations, the target wireless device may send DirectCommunication Release Accept message.

FIG. 21 shows an example of supporting a minimum required communicationrange between two UEs according to implementations of the presentdisclosure.

In step S2100, UE1 performs sidelink communication for unicast and/orgroupcast with UE2. In case of groupcast, UE1 can be one of groupmembers. UE1 may have required QoS information for the sidelinkcommunication. The required QoS information may be (pre-)configuredand/or provided from UE2. The required Qos information may includeinformation for minimum required communication range.

In some implementations, if UE1 is in RRC_CONNECTED and configured forgNB scheduled sidelink resource allocation (i.e., Mode 1), UE1 maytransmit sidelink UE information to the network. The sidelink UEinformation may include at least one of the followings: traffic patternof service A, transmission (TX) carriers and/or reception (RX) carriersmapped to service A, QoS information related to service A (e.g., 5QI,PPPP, PPPR, QoS class indicator (QCI) value), service type of service A(e.g., unicast, groupcast, broadcast) and destination related to serviceA and/or UE2 (e.g., destination ID, destination index or UE ID mapped toservice A and/or UE2).

In some implementations, after receiving the sidelink UE information,the network may construct sidelink configuration. The sidelinkconfiguration may include at least one of the followings: one or moreresource pools for service A and/or unicast transmission with another UEand Sidelink buffer status report (BSR) configuration such as mappingbetween a logical channel group (LCG) and one or more QoS values ormapping between a LCG and the service type of Service A. The network maysignal the sidelink configuration to UE1 and then UE1 may configurelower layers with sidelink configuration.

In some implementations, if a message becomes available in L2 buffer forsidelink transmission, UE1 may trigger scheduling request (SR) forsidelink signaling (e.g., a particular PSCCH or sidelink connectionestablishment), so that UE1 transmits PUCCH resource mapped to sidelinksignaling. If PUCCH resource is not configured, UE1 may perform randomaccess procedure as the scheduling request. If an uplink grant is givenat a result of the SR, UE1 may transmit sidelink BSR to the network. Thesidelink BSR may indicate at least a destination index or UE Index, aLCG, and a buffer size corresponding to the destination service, thedestination group or the destination UE. The destination index mayaddress the destination service, the destination group or thedestination UE. The UE index may address the destination/receiving UE.

In some implementations, after receiving the SL BSR, the network maytransmit a sidelink grant to UE1, e.g., by sending DCI in PDCCH. The DCImay include an allocated sidelink resource, the destination index and/orUE index. The index may be used to indicate the service A and/or UE2,explicitly or implicitly. If UE1 receives the DCI, UE1 may use thesidelink grant for transmission to UE2.

In some implementations, if UE1 is configured for UE autonomousscheduling of sidelink resource allocation (i.e., Mode 2), UE1 mayautonomously select or reselect sidelink resources to create a sidelinkgrant used for transmission to UE2.

In step S2102, UE1 performs to check/detect whether or not UE1 is out ofminimum required communication range. In step S2104, UE2 may transmitsignaling to enable UE1 to check/detect whether or not UE1 is out of theminimum required communication range.

In step S2106, UE1 detects that UE1 is out of the minimum requiredcommunication range. Then, in step S2108, UE1 suspends RBs and contextsfor sidelink communication with UE2, starts timer Txxx, and stopstransmission for sidelink communication with UE2.

In step S2110, UE1 sends a sidelink suspend request message to UE2 toinform that UE1 is out of the minimum required communication range andto request suspend

RBs and contexts for sidelink communication with UE1. The sidelinksuspend request message may include a cause information ‘out of theminimum required communication range’.

In step S2112, upon receiving the sidelink suspend request message fromUE1, UE2 decides whether or not continue sidelink communication withUE1. UE2 decides to continue sidelink communication with UE1.

In step S2114, upon deciding to continue sidelink communication withUE1, UE2 sends a sidelink resume message to UE1. The sidelink resumemessage may include information for an extended value of the minimumrequired communication range to resume RBs and contexts for sidelinkcommunication.

In step S2116, upon receiving the sidelink resume message from UE2, UE1stops the timer Txxx, resumes RBs and contexts for sidelinkcommunication and continues sidelink communication with UE1.

In some implementations, upon receiving a response message from UE2, UE1may stop the timer Txxx, resume RBs and contexts for sidelinkcommunication and continue sidelink communication with UE1.Alternatively, if there is no response message from UE2 during certaintime, UE1 may stop the timer Txxx, resume RBs and contexts for sidelinkcommunication and continue sidelink communication with UE1. The responsemessage may be a sidelink message sent by UE2 to confirm/request UE1suspend RBs and contexts for sidelink communication.

FIG. 22 shows another example of supporting a minimum requiredcommunication range between two UEs according to implementations of thepresent disclosure.

In step S2200, UE1 performs sidelink communication for unicast and/orgroupcast with UE2. In case of groupcast, UE1 can be one of groupmembers. UE1 may have required QoS information for the sidelinkcommunication. The required QoS information may be (pre-)configuredand/or provided from UE2. The required Qos information may includeinformation for minimum required communication range.

In some implementations, if UE1 is in RRC_CONNECTED and configured forgNB scheduled sidelink resource allocation (i.e., Mode 1), UE1 maytransmit sidelink UE information to the network. The sidelink UEinformation may include at least one of the followings: traffic patternof service A, transmission (TX) carriers and/or reception (RX) carriersmapped to service A, QoS information related to service A (e.g., 5QI,PPPP, PPPR, QoS class indicator (QCI) value), service type of service A(e.g., unicast, groupcast, broadcast) and destination related to serviceA and/or UE2 (e.g., destination ID, destination index or UE ID mapped toservice A and/or UE2).

In some implementations, after receiving the sidelink UE information,the network may construct sidelink configuration. The sidelinkconfiguration may include at least one of the followings: one or moreresource pools for service A and/or unicast transmission with another UEand Sidelink buffer status report (BSR) configuration such as mappingbetween a logical channel group (LCG) and one or more QoS values ormapping between a LCG and the service type of Service A. The network maysignal the sidelink configuration to UE1 and then UE1 may configurelower layers with sidelink configuration.

In some implementations, if a message becomes available in L2 buffer forsidelink transmission, UE1 may trigger scheduling request (SR) forsidelink signaling (e.g., a particular PSCCH or sidelink connectionestablishment), so that UE1 transmits PUCCH resource mapped to sidelinksignaling. If PUCCH resource is not configured, UE1 may perform randomaccess procedure as the scheduling request. If an uplink grant is givenat a result of the SR, UE1 may transmit sidelink BSR to the network. Thesidelink BSR may indicate at least a destination index or UE Index, aLCG, and a buffer size corresponding to the destination service, thedestination group or the destination UE. The destination index mayaddress the destination service, the destination group or thedestination UE. The UE index may address the destination/receiving UE.

In some implementations, after receiving the SL BSR, the network maytransmit a sidelink grant to UE1, e.g., by sending DCI in PDCCH. The DCImay include an allocated sidelink resource, the destination index and/orUE index. The index may be used to indicate the service A and/or UE2,explicitly or implicitly. If UE1 receives the DCI, UE1 may use thesidelink grant for transmission to UE2.

In some implementations, if UE1 is configured for UE autonomousscheduling of sidelink resource allocation (i.e., Mode 2), UE1 mayautonomously select or reselect sidelink resources to create a sidelinkgrant used for transmission to UE2.

In step S2202, UE1 performs to check/detect whether or not UE1 is out ofminimum required communication range. In step S2204, UE2 may transmitsignaling to enable UE1 to check/detect whether or not UE1 is out of theminimum required communication range.

In step S2206, UE1 detects that UE1 is out of the minimum requiredcommunication range. Then, in step S2208, UE1 suspends RBs and contextsfor sidelink communication with UE2, starts timer Txxx, and stopstransmission for sidelink communication with UE2.

In step S2210, UE1 sends a sidelink suspend request message to UE2 toinform that UE1 is out of the minimum required communication range andto request suspend RBs and contexts for sidelink communication with UE1.The sidelink suspend request message may include a cause information‘out of the minimum required communication range’.

In step S2212, upon receiving the sidelink suspend request message fromUE1, UE2 decides whether or not continue sidelink communication withUE1. UE2 decides not to continue sidelink communication with UE1. ButUE2 also decides to wait UE1 to come back to within the minimum requiredcommunication range.

In step S2214, upon deciding not to continue sidelink communication withUE1, but to wait UE1 to come back to within the minimum requiredcommunication range, UE2 suspends RBs and contexts for sidelinkcommunication with UE1, starts timer Txxx, stops transmission forsidelink communication with UE1 and sends a sidelink suspend message toconfirm/request UE1 suspend RBs and contexts for sidelink communication.However, UE2 continues to transmit signaling to enable UE1 tocheck/detect whether or not UE1 is out of the minimum requiredcommunication range if the signaling exits.

In some implementations, upon receiving the sidelink suspend message,UE1 may suspend RBs and contexts for sidelink communication with UE2 ifUE1 does not perform suspend RBs and contexts for sidelink communicationwith UE2 before. UE1 may start the timer Txxx if UE1 does not starttimer the Txxx before.

(1) Case I

In step S2216, before the timer Txxx expires, UE1 detects that UE1 isinside the minimum required communication range.

In step S2218, UE1 stops the timer Txxx and resumes RBs and contexts forsidelink communication with UE2.

In step S2220, UE1 sends a sidelink resume request message to informthat UE1 goes into within minimum required communication range and torequest resume RBs and contexts for sidelink communication with UE1.

In step S2222, upon receiving the sidelink resume request message fromUE1, UE2 sends a sidelink resume message to request UE1 to resume RBsand contexts for sidelink communication.

In step S2224, UE2 resumes RBs and contexts for sidelink communicationwith UE1. Upon receiving the sidelink resume message, UE1 stops thetimer Txxx, resumes

RBs and contexts for sidelink communication with UE2 and continuessidelink communication with UE2.

(2) Case II

Alternatively, in step S2226, the times Txxx expires. In step S2228, UE1and/or UE2 performs direct link release procedure. The direct linkrelease procedure may be performed implicitly or explicitly.

FIG. 23 shows another example of supporting a minimum requiredcommunication range between two UEs according to implementations of thepresent disclosure.

In step S2300, UE1 performs sidelink communication for unicast and/orgroupcast with UE2. In case of groupcast, UE1 can be one of groupmembers. UE1 may have required QoS information for the sidelinkcommunication. The required QoS information may be (pre-)configuredand/or provided from UE2. The required Qos information may includeinformation for minimum required communication range.

In some implementations, if UE1 is in RRC_CONNECTED and configured forgNB scheduled sidelink resource allocation (i.e., Mode 1), UE1 maytransmit sidelink UE information to the network. The sidelink UEinformation may include at least one of the followings: traffic patternof service A, transmission (TX) carriers and/or reception (RX) carriersmapped to service A, QoS information related to service A (e.g., 5QI,PPPP, PPPR, QoS class indicator (QCI) value), service type of service A(e.g., unicast, groupcast, broadcast) and destination related to serviceA and/or UE2 (e.g., destination ID, destination index or UE ID mapped toservice A and/or UE2).

In some implementations, after receiving the sidelink UE information,the network may construct sidelink configuration. The sidelinkconfiguration may include at least one of the followings: one or moreresource pools for service A and/or unicast transmission with another UEand Sidelink buffer status report (BSR) configuration such as mappingbetween a logical channel group (LCG) and one or more QoS values ormapping between a LCG and the service type of Service A. The network maysignal the sidelink configuration to UE1 and then UE1 may configurelower layers with sidelink configuration.

In some implementations, if a message becomes available in L2 buffer forsidelink transmission, UE1 may trigger scheduling request (SR) forsidelink signaling (e.g., a particular PSCCH or sidelink connectionestablishment), so that UE1 transmits PUCCH resource mapped to sidelinksignaling. If PUCCH resource is not configured, UE1 may perform randomaccess procedure as the scheduling request. If an uplink grant is givenat a result of the SR, UE1 may transmit sidelink BSR to the network. Thesidelink BSR may indicate at least a destination index or UE Index, aLCG, and a buffer size corresponding to the destination service, thedestination group or the destination UE. The destination index mayaddress the destination service, the destination group or thedestination UE. The UE index may address the destination/receiving UE.

In some implementations, after receiving the SL BSR, the network maytransmit a sidelink grant to UE1, e.g., by sending DCI in PDCCH. The DCImay include an allocated sidelink resource, the destination index and/orUE index. The index may be used to indicate the service A and/or UE2,explicitly or implicitly. If UE1 receives the DCI, UE1 may use thesidelink grant for transmission to UE2.

In some implementations, if UE1 is configured for UE autonomousscheduling of sidelink resource allocation (i.e., Mode 2), UE1 mayautonomously select or reselect sidelink resources to create a sidelinkgrant used for transmission to UE2.

In step S2302, UE1 performs to check/detect whether or not UE1 is out ofminimum required communication range. In step S2304, UE2 may transmitsignaling to enable UE1 to check/detect whether or not UE1 is out of theminimum required communication range.

In step S2306, UE1 detects that UE1 is out of the minimum requiredcommunication range. Then, in step S2308, UE1 suspends RBs and contextsfor sidelink communication with UE2, starts timer Txxx, and stopstransmission for sidelink communication with UE2.

In step S3210, UE1 sends a sidelink suspend request message to UE2 toinform that

UE1 is out of the minimum required communication range and to requestsuspend RBs and contexts for sidelink communication with UE1. Thesidelink suspend request message may include a cause information ‘out ofthe minimum required communication range’.

In step S2312, upon receiving the sidelink suspend request message fromUE1, UE2 decides whether or not continue sidelink communication withUE1. UE2 decides not to continue sidelink communication with UE1. UE2also decides to not wait UE1 to come back to within the minimum requiredcommunication range.

In step S2314, upon deciding not to continue sidelink communication withUE1, and not to wait UE1 to come back to within the minimum requiredcommunication range, UE2 performs direct link release procedure withUE1. The direct link release procedure may be performed implicitly orexplicitly.

The present disclosure can have various advantageous effects.

For example, one wireless device can perform fast and reliable sidelinkcommunication for unicast and/or groupcast (or group communication) tosupport a minimum required communication range by minimizing inefficientsignalling overheads.

For example, a system can provide fast and reliable sidelinkcommunication for unicast and/or groupcast (or group communication) tosupport a minimum required communication range.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

Claims in the present disclosure can be combined in a various way. Forinstance, technical features in method claims of the present disclosurecan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod. Other implementations are within the scope of the followingclaims.

1. A method for a first wireless device in a wireless communicationsystem, the method comprising: performing a transmission with a secondwireless device; detecting that the second wireless device is out of aminimum required communication range; and suspending the transmissionwith the second wireless device.
 2. The method of claim 1, wherein thatthe second wireless device is out of the minimum required communicationrange is detected by receiving, from the second wireless device,information that the second wireless device is out of the minimumrequired communication range.
 3. The method of claim 1, wherein thetransmission with the second wireless device is suspended except forsignaling to enable the second wireless device to identity whether ornot the second wireless device is in the minimum required communicationrange.
 4. The method of claim 1, wherein a radio bearer related to theminimum required communication range is suspended.
 5. The method ofclaim 1, wherein contexts of the second wireless device are held uponsuspending the transmission with the second wireless device.
 6. Themethod of claim 1, wherein information for suspension of thetransmission with the second wireless device is transmitted to thesecond wireless device.
 7. The method of claim 1, wherein a timer startsupon detecting that the second wireless device is out of the minimumrequired communication range.
 8. The method of claim 7, wherein thetransmission with the second wireless device is resumed upon detectingthat the second wireless device is in the minimum required communicationrange before expiry of the timer.
 9. The method of claim 8, wherein thatthe second wireless device is in the minimum required communicationrange is detected by receiving, from the second wireless device,information that the second wireless device is in the minimum requiredcommunication range.
 10. The method of claim 7, wherein the transmissionwith the second wireless device is released upon expiry of the timer.11. The method of claim 1, wherein the transmission with the secondwireless device includes at least one of a unicast sidelinkcommunication and/or a groupcast sidelink communication.
 12. The methodof claim 11, wherein the minimum required communication range is for theunicast sidelink communication and/or for the groupcast sidelinkcommunication.
 13. The method of claim 1, wherein the first wirelessdevice is in communication with at least one of a mobile device, anetwork, and/or autonomous vehicles other than the first wirelessdevice.
 14. A wireless device in a wireless communication system, thewireless device comprising: at least one transceiver; at leastprocessor; and at least one computer memory operably connectable to theat least one processor and storing instructions that, based on beingexecuted by the at least one processor, perform operations comprising:performing a transmission with a second wireless device; detecting thatthe second wireless device is out of a minimum required communicationrange; and suspending the transmission with the second wireless device.